Switchable Cavitation in Silicone Coatings for Energy-Saving Cooling and Heating

Space cooling and heating currently result in huge amounts of energy consumption and various environmental problems. Herein, a switching strategy is described for efficient energy-saving cooling and heating based on the dynamic cavitation of silicone coatings that can be reversibly and continuously tuned from a highly porous state to a transparent solid. In the porous state, the coatings can achieve efficient solar reflection (93%) and long-wave infrared emission (94%) to induce a subambient temperature drop of about 5 degrees C in hot weather (approximate to 35 degrees C). In the transparent solid state, the coatings allow active sunlight permeation (95%) to induce solar heating to raise the ambient temperature from 10 to 28 degrees C in cold weather. The coatings are made from commercially available, cheap materials via a facile, environmentally friendly method, and are durable, reversible, and patternable. They can be applied immediately to various existed objects including rigid substrates.